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<meta charset="utf-8"> 
<title>菜鸟教程(runoob.com)</title> 
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body
{
	background-image:url('https://static.runoob.com/images/mix/gradient2.png');/*把图像设置为背景*/
}
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<h1>Hello World!</h1>
<p>默认情况下 background-image 属性会在页面的水平或者垂直方向平铺</p>
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